Canon DR-5010C - Manual (Page 79)

Regular Maintenance 77
Removing and Attaching the Retard Roller
Follow the procedure below to remove and attach the retard roller when you
clean or replace it.
CAUTION
Do not use excessive force when removing or attaching the
rollers. Doing so may damage them.
Removing the Retard Roller
1.
Hold the Upper unit as shown in the diagram, and open it slowly until it stops.
CAUTION
The pickup roller is located in the middle of the Upper unit. Do not
hold the protrusion on the Upper unit when you open it. Doing so
may deform the pickup roller or cause a feed error.
2.
Remove the roller cover.